Residual Cd Research Articles

Metal partitioning and relationships to soil microbial properties of submerged paddy soil contaminated by electronic waste recycling

The interactions between microbial properties and metal partitioning were investigated in paddy soils during the cultivation of rice in field experiments. Samples from an electronic waste-recycling centre (e-waste centre) were used as the contaminated sample. Multiple regressions analysis showed that activity of soil enzymes and the abundance of microbial physiological groups were affected by residual Cd, residual Zn, exchangeable Cu, exchangeable Zn and Fe–Mn-oxidising Cd. The residual Cd concentration could predict 66.7, 35.5 and 62.4% of the variance in the activity of sulfate reductase, peroxidase and urease, respectively, while the concentrations of exchangeable Cu, exchangeable Zn and Fe–Mn-oxidising Cd explained 43.2, 9.9 and 65.2% of the variance in catalase, sulfate reductase and acid phosphatase, respectively. The contents of residual Cd and residual Zn could predict 89.0 and 42.7%, respectively, of the variations in the abundance of total bacteria and metal-resistant bacteria. However, metal partitioning was affected by soil microorganisms. Organic Zn and Fe–Mn-oxidising Cd were easily affected by soil bacteria and sulfur-oxidising bacteria. The abundance of soil bacteria explained 69.8 and 64.7% of the variance in organic Zn and Fe–Mn-oxidising Cd, and sulfur-oxidising bacteria explained 21.0% of the variance in Fe–Mn-oxidising Cd.

Biosorption of Cd(II) from Water by <i>Moringa oleifera</i> Leaves

Cadmium is one of the most toxic metals affecting man, animals, and plants. It is considered one of the priority pollutants, its excretion from the body is very low, and it has synergistic toxicity with other metals. Therefore, cadmium from surface water and wastewater where the cadmium level is high must be treated. This work was done to study the biosorption of Cd (II) from water using Moringa oleifera leaves, as a natural, low cost biosorbent, and environmentally friendly without any modification. The dosage and the particle size of the natural biosorbent were studied as well as the concentration of Cd (II), and pH. The synthetic water with initial turbidity of 200 NTU was used and the Cd (II) concentration was 1ppm, and 3ppm. Different dosages of Moringa oleifera leaves powder of (0.10 to 10 g/L) were added with different particle size of Moringa oleifera leaves (<125, <250, <500, and >500 μm) at room temperature. The AAS was used to measure the residual Cd (II) in the supernatant after treatment with Moringa oleifera leaves powder. It was observed that the removal of Cd (II) was increased by increasing the natural biosorbent dosage, while the particle size and the pH has no effect on the removal efficiency. Therefore, it is concluded that the Moringa oleifera leaves powder can be used as a natural biosorbent without any chemical modification and can be used directly after grinding without sieving to different sizes. The best removal of 1ppm, and 3ppm Cd (II) was at dosage of 8g/L, and 10g/L from fresh grinded leaves, respectively.

Influence of digestion methods on the recovery of Iron, Zinc, Nickel, Chromium, Cadmium and Lead contents in 11 organic residues

There are currently many devices and techniques to quantify trace elements (TEs) in various matrices, but their efficacy is dependent on the digestion methods (DMs) employed in the opening of such matrices which, although "organic", present inorganic components which are difficult to solubilize. This study was carried out to evaluate the recovery of Fe, Zn, Cr, Ni, Cd and Pb contents in samples of composts and cattle, horse, chicken, quail, and swine manures, as well as in sewage sludges and peat. The DMs employed were acid digestion in microwaves with HNO3 (EPA 3051A); nitric-perchloric digestion with HNO3 + HClO4 in a digestion block (NP); dry ashing in a muffle furnace and solubilization of residual ash in nitric acid (MDA); digestion by using aqua regia solution (HCl:HNO3) in the digestion block (AR); and acid digestion with HCl and HNO3 + H2O2 (EPA 3050). The dry ashing method led to the greatest recovery of Cd in organic residues, but the EPA 3050 protocol can be an alternative method for the same purpose. The dry ashing should not be employed to determine the concentration of Cr, Fe, Ni, Pb and Zn in the residues. Higher Cr and Fe contents are recovered when NP and EPA 3050 are employed in the opening of organic matrices. For most of the residues analyzed, AR is the most effective method for recovering Ni. Microwave-assisted digestion methods (EPA3051 and 3050) led to the highest recovery of Pb. The choice of the DM that provides maximum recovery of Zn depends on the organic residue and trace element analyzed.

Effects of electrokinetic treatment of contaminated sludge on migration and transformation of Cd, Ni and Zn in various bonding states

This study assesses the effect of electrokinetic processes on the migration and bonding states of various heavy metals in municipal sludge. The transformation and migration are discussed through the examination of sludge characteristics and distribution of Cd, Zn and Ni after electrokinetic treatments. The migration and distribution of the contaminants after the electrokinetic treatments were determined for each sludge sample by sequential extraction. The noticeable changes on the average speciation fractions of Cd, Zn and Ni were observed that oxidizable heavy metals increased and reducible fraction decreased due to the application of voltage. Bivariate correlation analysis indicated that the amounts of different bonding states of Zn and Ni were significantly correlated (P<0.05) with durations and resistance. The oxidizable Zn was negatively correlated with exchangeable and reducible Zn. Moreover, reducible Zn had a close negative relationship with residual Zn. The bonding state of Ni was significantly related to the durations of electrokinetic processes, indicating the existing of mutual transformation between different speciation fractions over time. The analysis also indicated that the exchangeable Cd showed a close negative relationship with reducible Cd (P<0.01), whereas the reducible Cd was negatively related to residual Cd (P<0.05).

Symbol Spaced Adaptive MIMO Equalization for Ultrahigh Bit Rate Metro Coherent Optical Links

A novel approach to symbol spaced adaptive multiple-input-multiple-output (MIMO) equalization is proposed. Different functionalities are defined for static versus adaptive equalizers, to minimize noise enhancement. Static equalizers are used for anti-aliasing filtering and bulk CD compensation, and a newly proposed modified-LMS-based adaptive MIMO equalizer is used to compensate for fiber random impairments such as residual CD and PMD. In addition, the proposed technique enables the use of low-cost reduced bandwidth components in both transmit and receive sides, and supports aggressive in-line optical filtering in the existing WDM network. Moreover, the proposed technique perfectly suits coherent metro applications, allowing significant power savings in application specific integrated circuit implementation.

Evaluation of Lead and Cadmium Heavy Metal Residues in Milk and Milk Products Sold in Ogbomoso, Southwestern Nigeria

The concentrations of lead (Pb) and cadmium (Cd) heavy metals in cow milk, goat milk butterfat, soft cheese and yoghurt samples were evaluated. Forty samples (eight of each sample) were analyzed using the atomic absorption spectrophotometer. There were detectable residual concentrations of Pb and Cd in all the 40 samples. The range of 0.0025 to 0.0061 ppm of Pb concentrations in the samples was within the Maximum Residue Limit (MRL) of 0.0125 to 0.0175 ppm of Pb in milk and dairy products. There was a significantly (P 0.05) different from that of the goat milk samples. Residual concentrations of Cd were higher in soft cheese samples (0.0048±0.0007 ppm) and in goat milk samples (0.0045±0.0005 ppm Cd) and these two concentrations exceeded the MRL of 0.0035 ppm of Cd recommended by India regulations. The residual concentration of Cd in goat milk samples (0.0045±0.0005 ppm) was significantly (P<0.05) higher than in the cow milk samples (0.0021±0.0007 ppm). The results of this study showed that all the milk and milk products samples analyzed contained residues of Pb and Cd heavy metals. The observation of residual Cd concentrations above the MRLs in the soft cheese samples and in the goat milk samples is of public health concern and could cause health hazards to consumers.

Investigating the role of key ingredients on cathodic delamination resistance of high-build pigmented epoxy coatings

Organic coatings applied on cathodically protected metallic structures must have good resistance to cathodic delamination or disbonding (CD). Both environmental conditions and coating composition influence the CD resistance. In the present study, the effect of types of epoxy resin, curing agents and their mixing ratio on cathodic delamination rate was studied in a high-build pigmented coating. Furthermore, the influence of platey fillers on CD resistance was also studied. In order to bring out correlations, if any, between adhesion and CD resistance, pull-off adhesion strengths (both dry and wet) of these coatings were also measured. Fairly good correlation was found between residual (wet) pull-off adhesion strength and CD resistance. When tested at 60 and 90°C, all the coatings under investigation showed chalking. Among the coatings under investigation, the one based on Bisphenol F epoxy and modified cycloaliphatic amine adduct exhibited excellent CD resistance.

Comparative in situ remediation potential of Pseudomonas putida 710A and Commamonas aquatica 710B using plant (Vigna radiata (L.) wilczek) assay

A greenhouse study was conducted to determine the effect of cadmium (Cd)-resistant Pseudomonas putida strain 710A and Commamonas aquatica strain 710B, used either alone or as a binary mixture on the toxicity of cadmium to mungbean [Vigna radiata (L.) wilczek] plants. The bacterial strains 710A and 710B, isolated from the Semra mines in Ranchi, India, were resistant to 0.5 mM and 1 mM, CdCl2 respectively. Moreover, both strains grew well at 10 °C and 30 °C. Of the two bacterial strains, strain 710B showed 129.6 and 83.5 times higher P solubilizing activity than strain 710A, when grown in liquid broth supplemented with cadmium at 10 °C and 30 °C, respectively. Furthermore, 16S ribosomal DNA (rDNA) sequencing identified 710A as a Pseudomonas putida strain and 710B as a Commamonas aquatica strain. The strain 710A significantly (p < 0.05) stimulated the growth of roots (35.2 %) and shoots (30 %) of mungbean plants grown in soil treated with 110 μM CdCl2. However, the increase in the case of 710B was found to be 15.4 % and 5.17 %, respectively. The loss of chlorophyll content was replenished by up to 80 %, 66 %, and 77.3 % by inoculation of 710A, 710B and binary mixture, respectively. Moreover the strains were able to reduce Cd accumulation in roots and shoots. Most significantly, residual Cd concentration in soil was reduced in the presence of bioinoculants. However, in terms of efficiency, the strains were found to be in the following order: 710A > 710A +710B > 710B. The results suggest that P. putida 710A strain is a potentially effective candidate metal to be used for sequestering and as a growth-promoting bioinoculant in Cd polluted soil.

Evolution of Heavy Metals Leachability and Speciation in Residues of Sewage Sludge Treated by Microwave assisted Pyrolysis

In this study the sewage sludge are treated by microwave assisted pyrolysis (MAP) with different microwave receptors, and then, the immobilization of heavy metals in the residues are evaluated through the toxicity characteristic leaching procedure (TCLP) and sequential extraction procedure. The volatilization of Cd, Pb and Zn could be decreased by MAPs more efficiently than the conventional pyrolysis (CP). The average leaching percentages of Cu, Zn and Pb in residues produced by MAPs are decreased 90%, 88% and 81% more than the CP process respectively, and no leaching Cd is detected. Moreover, more than 67% of Cu, Pb, Zn and 55% of Cd in residues of MAP speciated into stable phase, which is higher than the metals in the residues of CP. The effect of heavy metals stabilized in residues of MAP was determined in the order as Cd &gt; Cu &gt; Pb &gt; Zn. The results suggest the immobilization of heavy metals in the residues are enhanced in the process of MAP. This novel approach should be of significance in immobilizing heavy metals in residues of sewage sludge.

Influence of Inorganic Salts on Concentration of Different Cd Forms in the Soil

Different soluble inorganic salts were irrigated into batches of soil samples by setting contrastive experiments on the basis of Tessier sequential extraction procedure to study their influences upon Cd forms in the soil. Research shows that all the three salts were able to influence the forms of Cd in the soil: NaCl and Na2SO4 added into the soil could increase the contents of exchangeable Cd and the higher the concentration, the greater the impact, while Na2CO3 could decrease it by 30.35%(4 g/kg Na2CO3 added) and 69.87%(8 g/kg Na2CO3 added). Carbonate content of Cd was influenced obviously by NaCl, with the decrease of 7.30%, 10.52% corresponding to low concentration and high concentration of NaCl, and Na2CO3 can increase this form slightly, Na2SO4 had little effect, so the content remained unchanged. The Fe-Mn oxidation form of Cd remained the original level when NaCl was added in the samples while it increased with the addition of Na2CO3 obviously and the concentration increased 8.67% (4 g/kg Na2CO3 added) and 51.85% (8 g/kg Na2CO3 added),but it decreased by the effect of Na2SO4. Organic Cd and the residual Cd fluctuated slightly at a very low concentration. The total Cd decreased with the addition of sodium salt.

Screening of extraction methods for Cd and As bioavailability prediction in rhizospheric soil using multivariate analyses

Heavy metals in tailings and mining wastes from abandoned mines can be released into adjacent agricultural field and bioaccumulated in crops or vegetables. Therefore, prediction of metal bioavailability has become an important issue to prevent adverse effect of bioaccumulated metals on human health. In this study, single and sequential extraction methods were compared using multivariate analysis to predict the bioavailability of Cd and As in contaminated rhizosphere soils. Single extraction using 0.1 M HCl for Cd and 1.0 M HCl for As had an extraction efficiency of 8–12% for soil Cd and 14–17% for soil As compared to total concentration extracted with aqua regia. Using sequential extraction, Fe–Mn-bound Cd (FR3) and residual Cd (FR5) were the dominant fractions representing 43 and 41% of total Cd concentration. For As, the strongly absorbed form (FR2) was the most abundant chemical fraction showing 45–54% of the total As concentration in soil. Multivariate analyses showed that single extraction with HCl and total concentration of Cd and As in soil were significantly correlated to potato and green onion plant tissue metal concentration. Although little information was obtained with multiple regression analysis because of multicollinearity of variables, the result of principle component analysis (PCA) revealed that the highest positive loading was obtained using total concentration of Cd and As in soil in the first principle component (PC1). In addition, total concentration of Cd and As in soil was independently grouped with other chemical fractions by cluster analysis. Therefore, the overall result of this research indicated that total concentrations of Cd and As in rhizosphere soils were the best predictors of bioavailability of heavy metals in these contaminated soils.

Field Application of Particle Filtration with EPP (Expanded Polypropylene) Engineered Media of Road Runoff

Metal elements or other constituents transported in urban and transportation land use rainfall runoff are often adsorbed on or incorporated with entrained particles that are ubiquitous in such runoff. EPP(Expanded Polypropylene) engineered media with a large surface area was developed to treat road runoff. Field application of particle filtration reactor(PFR), which combined the EPP engineered media with filtration called EcoTank system, provided control of water quality. Under the operating conditions with 0.55 hours hydraulic retention time(HRT) and a capable of treating a maximum road runoff 9.5 m3/h, the mean residual Cd, Cr, Cu, Pb and Zn were 0.24, 2.8, 13.4, 11 and 112.3 ㎍/L and corresponding percentage mean removal values were 91, 93, 85, 91 and 80%, respectively. Results suggest that a properly designed PFR can provide effective in situ control for particles and could be combined with or function separately from source control.

Facilitated desorption and stabilization of sediment-bound Pb and Cd in the presence of birnessite and apatite

Desorption of lead (Pb) and cadmium (Cd) from contaminated sediments was investigated to clarify the effect of stabilizing agents on Cd and Pb desorption kinetics. The desorbed aqueous Cd and Pb concentrations and the residual amounts of Cd on the sediments in the desorption tests were best fitted to a pseudo-second-order kinetics with the highest R 2 values among the models used in the kinetic studies. The average residual Cd on sediments were 24% and 19% less in the presence of apatite and birnessite, respectively, than in the absence of them. However, the Pb desorption was not affected by the stabilizing agents. The negligible aqueous concentrations of desorbed Cd and Pb in the presence of apatite and birnessite suggest the stabilization of desorbed Cd that was facilitated by apatite and birnessite and Pb. The kinetics study with Cd shows that the rate constants are not affected, but the desorption extents are affected in the presence of apatite and birnessite. The Tessier sequential extraction method and toxicity characteristic leaching procedure indicate that Pb is more strongly bound on the stabilizing agents than Cd. Overall, birnessite and apatite can be successfully applied in remediation of Cd and Pb contaminated sediment.

Total concentrations and chemical speciation of heavy metals in liquefaction residues of sewage sludge

The risk (including bioavailability and eco-toxicity) of heavy metals (Pb, Zn, Cu, Cd, Cr and Ni) in liquefaction residues (LR) of sewage sludge (SS) was estimated, according to both the speciation of heavy metals and the local environmental characteristics. The amount of organic matters in LR was lower than that in SS, resulting in a smaller calorific value, while the total content of heavy metals in LR nearly doubled. High residual rates of heavy metals (about 80%) indicated that the heavy metals in SS were concentrated into LR after liquefaction. The comparisons of sequential extraction results between SS and LR showed that after liquefaction, the mobile and easily available heavy metal fractions (acid soluble/exchangeable and reducible fractions) were mainly transformed into the relatively stable heavy metal fractions (oxidizable and residual fractions). The bioavailability and eco-toxicity of heavy metals in LR were relieved, though the total concentrations of heavy metals increased.

Effects and mechanisms of amendments on remediation of cadmium contaminated acid paddy soils

A field experiment was conducted to study Cd immobilization in Cd contaminated soils. The study analyzed the remediation effects of lime (L), fused calcium magnesium phosphate (P), sepiolite (S), humic acid (H) and mixed lime amendments (LP, LS and LH) on Cd bioavailability in a Cd contaminated acid paddy soils. The results indicate that amendments significantly change the proportion of Cd forms in contaminated soils. Except for H, the other 3 amendments lower acid extractable fraction of Cd, while increasing oxidation fraction and residual Cd. The 4 amendments reduce the 0.1 mol·L-1 NaNO3 and 0.01 mol·L-1 CaCl2 extracted Cd by 26%～97%. The order of reduction is LS S LP P L LH H. The content of Cd in the aboveground parts of rice decreases by 6%～49% under amendment application. Amendment increasing soil pH is the main factor influencing soil Cd immobilization. In conclusion therefore, sepiolite could be a suitable amendment of Cd contaminated acid paddy soils. However, humic acid is not so suitable for remediating Cd contaminated acid paddy soils.

Redistribution of residual Pb, Zn, and Cd in soil remediated with EDTA leaching and exposed to earthworms (Eisenia fetida)

After soil remediation with ethylenediamine tetraacetate (EDTA) leaching/washing, the residual Pb, Zn, and Cd species are left in the soil in non‐labile forms. The effect of earthworms as main soil biotic factors on the residual Pb, Zn, and Cd fraction lability (mobility, bioavailability to plants, and oral‐availability) was investigated. Contaminated soil from a smelter site was treated with increasing EDTA concentrations (2.5 to 4‐times 40 mmol kg−1) to gradually reduce the heavy metal content and lability. Leached soils were processed by Eisenia fetida and heavy metal lability and fractionation determined in casts and earthworm‐processed soils. In general E. fetida increased heavy metal accessibility/mobility, but the induced changes diminished with the intensity of soil EDTA treatment. Fractionation results indicate the possibility of a time‐dependent complexation of heavy metals to carbonates favoured by earthworms’ gut processes. The transition of residual heavy metals in time (ageing) should be considered.

Comparison of oyster shell and calcium hydroxide as liming materials for immobilizing cadmium in upland soil

Cadmium is both readily available and highly toxic to plants and animals. Our objectives were to evaluate the effect of oyster shell as a liming material on reducing plant cadmium (Cd) uptake and to compare oyster shell and Ca(OH)2, a common liming material in Korea. Ground oyster shell and Ca(OH)2 were applied at 0, 2, 4, and 8 Mg Ca per hectare to an upland soil contaminated manually with CdSO4 (total Cd 8.96 mg kg−1). Radish (Raphanus sativa L.) was sown on the contaminated soil. Oyster shell was less effective at increasing soil pH and net negative charge than Ca(OH)2, but more effective at suppressing radish Cd uptake in both roots and shoots. The portion of Cd that is strongly bound to soil (fraction 5) increased more with oyster shell than with Ca(OH)2. Radish plant Cd concentration was positively correlated with 0.1 N HCl-extractable Cd and negatively correlated with the residual Cd fraction (F5), indicating that an increase in the strongly bound Cd fraction played an important role in reducing radish Cd uptake in soil to which oyster shell was applied. The greater potential of oyster shell to decrease Cd extractability in soil and plant Cd uptake compared to Ca(OH)2 might be attributed to the layered morphology of oyster shells. Based on these results, oyster shell could be a very good alternative liming material to reduce Cd phytoavailability in Cd-contaminated soil.

Sepiolite is recommended for the remediation of Cd-contaminated paddy soil

This study aimed to assess the extractability of cadmium (Cd) and Cd uptake by rice after applying soil amendments of lime (Ca(OH)2) and sepiolite. A rice (Oryza sativa) cultivation experiment was conducted in a Cd-contaminated paddy field. After applying lime, sepiolite, and a mixture of the two as soil amendments, soil pH showed a significant increase (p<0.05), and Cd in soil extracted with NaNO3, CaCl2, and DTPA, was reduced by 61–100%, 52–98%, and 12–15%, respectively (p<0.05). The amount of exchangeable Cd showed a significant decrease in all treatments (p<0.05), and we found increases in the proportion of forms of carbonate-bound, Fe/Mn oxide-bound, and residual Cd in the soils, as measured by a sequential extraction method. The grain or rice straw biomass was neither significantly influenced by any amendment in the experiment, while the uptake of Cd by rice significantly decreased in all treatments (p<0.05). The results reveal no advantage in applying a mixture of sepiolite and lime compared with applying sepiolite alone in immobilizing Cd in the soil. The use of sepiolite or sepiolite mixed with lime was more effective than the use of lime alone in the immobilization of Cd in the soil. We therefore recommend sepiolite as a soil amendment to remediate Cd-contaminated paddy soil.

Fractionation of copper and cadmium and their binding with soil organic matter in a contaminated soil amended with organic materials

Purpose The contamination of agricultural soils by heavy metals is a worldwide problem. Organic amendments can be used for the immobilization and binding of heavy metal ions in soils by complexation, adsorption, and precipitation. A field trial was carried out to evaluate the influence of some low-cost organic materials such as rice straw (RS), green manure (GM), and pig manure (PM) on the distribution of Cu and Cd and the retention of these metals by organic matter fractions in heavy metal-polluted soils. Materials and methods The experiment was conducted in Miaoyunao Village, Daye County, Hubei province, China. PM, GM (peanut plants), and RS were obtained from a farm close to the village. Sixteen treatments with three replicates were designed. Soil chemical properties such as soil pH, electrical conductivity (EC), organic matter (OM), and available P were measured by standard methods. Soluble/ exchangeable, organic-bound, inorganic precipitates and residual Cu and Cd in the soil were sequentially extracted and analyzed. The amounts of Cu and Cd bound with soil particulate organic matter (POM) fractions and humic substances were also determined. Results and discussion The addition of organic amendments declined significantly the concentrations of soluble/ exchangeable Cu and Cd, but increased the amounts of these metals in organic-bound and inorganic precipitate forms in the soil. RS was more effective than GM and PM in diminishing the solubility of Cu and Cd. The largest retention for Cu and Cd by humic substances and POM was noticedinRStreatments,whereasthelowestwasfoundinPM treatments. Humic substances showed higher potential in the fixation of Cu and Cd than POM fractions. The conversion of soluble/exchangeable Cu and Cd to other insoluble forms after the application of organic amendments may be ascribed to the increases of soil OM, pH, EC, and available P contents. The highest binding of Cu and Cd with POM fractions and humic substances after the incorporation of RS mainly resulted from the greatest increase of soil OM contents. Conclusions RS, GM, and PM can be employed as good and cheap substances for the immobilization of Cu and Cd in heavy metal-polluted soils. RS was the best amendment in decreasing the solubility of Cu and Cd, and also in enhancing the retention of these metals by humic substances and POM fractions in the soil. Futures studies should focus on the influence of these organic amendments or their mixtures on the phytotoxicity of Cu and Cd for different plants in heavy metal-contaminated soils.

Fabrication of Composite Material from Sea Mussel Shells and White Clay as a Versatile Sorbent

Problem statement: The removal of heavy metals contaminated in aqueous solution/wastewater has been causing worldwide concern. However, the adsorbent materials are usually limited due to their high cost and environmentally benign. To overcome the above-mentioned disadvantages, low-cost and effective adsorbents are in demand. Approach: In this study, the sea mussel shells/natural clay beads were prepared for using as low-cost sorbent to remove Cd in the synthetic wastewater. Results: The sorbent were characterized using Scanning Electron Microscopy (SEM). The adsorption of Cd(II) ions from aqueous solution onto adsorbent has been investigated using kinetic approach to evaluate the effect of initial concentration and contact time on the removal of Cd. In adsorption studies, residual Cd(II) ion concentration reached equilibrium in duration of 240 min for initial Cd concentration of 5 ppm. The maximum removal achieves 99.75 mg g-1. Conclusion/Recommendations: The present results suggest that the adsorbent derived from sea mussel shells/natural clay bead is expected to be an economical material for removal of Cd(II) ions effectively from contaminated water.